Lubricants



'ence-to the following examples:

United States Patent 2,876,199 LUBRICANTS Jones I. Wasson and William "C. Howell, Jr'., Union Township, Union County, N. J., assignors to Esso Research and Engineering Company, -acorporation of Delaware NoDrawing. Application April 22, 1955 Serial No. 503,326

3'Claims. (Cl.25255) This invention relates to open gearlubricatingcom.- positions. Particularly, the invention relates to improved open gear lubricants which comprise mixtures of asphaltic materials and highly aromatic solvent-extract oils having low viscosity indices and low aniline points.

In the past, gear lubricants have been made from blends of asphaltic materials and mineral oils. The asphaltic materials used have been generally selected from a wide range of petroleum crude oil residua and the mineral oil components of the blend have been usually of the mixed base or naphthenic type. The viscosity of the diluent oils have ranged from about 60 to about 300 SUS/210 F.

It has not been hitherto appreciated that the type and viscosity index of diluent oil used in the manufacture of open gear lubricants was of any importance. It has now been discovered, however, and forms the object of this invention that superior gear oils are obtained from blends of asphalts with diluent oils having a high aromatic content, particularly those having aniline points from about 80 to about 120 F. and viscosity indices below about O. It has been found that these aromatic type oils have excellent solvent properties for asphalts and the blends-approach true solution. This is in contrast to the gels or semi-gels obtained upon blending asphalt or asphaltic materials with relatively high viscosityindex oils having low solventproperties for asphalts.

The blends prepared in accordance with this invention give outstanding lives on open gears, which is believed to be due to the unusual metal-adhering properties and to their ability to maintain lubricant films on Working parts because of their superior fluidity and stringiness'. These properties of improved metal adherence and superior fluidity or solution properties are obtained by use of the particular diluent oils, which is the-gist of the'inventive concept.

The invention will be more clearly explained by referformed using different asphaltic materials anddifierent 2,876,199 Patented Mar. 3, 1959 Table I..Dil u ent oil inspections ,vis. 210F. V Aniline Designation, Gravity I (SUS) V. I 1521131)? 0.9982 ass I aao 11s -Diluent oils A and B represent the prior art diluent oils. It will be noted that they have viscosity indices of 17 and 4.9, respectively, and aniline points of 218 and F., indicating a low aromatic content. Diluent oils C-F are highly aromatic extracts from mineral oils. Diluent oil C, is. an extract obtained. by the silica gel extraction of a distillate, whereas diluent oils D, E, and F were obtained by phenol extraction. It will thus be seen that blends prepared from either asphalt A or B with diluent oils A and B represent the prior art gear lubes, whereas with diluent oils O-Fblends are prepared in accordance with the in- .ventive concept..

Various proportions of the asphalts. and diluents describedabove were blended by admixing the two chosen materials and heating with agitation until solutions were obtained; This method of preparation of the gear lubridynamometer for. measuring the gear load. The gears are lubricated with the lubricant to be tested and are run ata temperature of from 8,0" to 90 F., at uniform pinion gearspeed of 400 R. P. ,M., and a load of. 750 lbs. per tooth until the lubricant wears off the gear teeth and .exposes free metallic surfaces. The hours to exposure of free metal is reported as thelubricating life of the lubricant.

The resultsof subjecting the .open gear lubricants .of

Examples 1-16 to this test are set out in Table H below.

Table II.-Gear rigtest results Asphalt (wt'.

Diluent O11 (wt.-perce11t) Gear Rig like.

amples- 6 and 7, to the inventive blends, Examples 8 and 9, at the 2000 viscosity level. The advantages of the latter are obvious. In Examples 10-12, blends at the 2500 viscosity level are compared, and in Examples 13 -16, blends at the 4,000-5,000 viscosity level are compared. An outstanding advantage is shown at both these viscosity levels for the gear lubricants of this invention.

ASPHALTIC MATERIAL The asphaltic materials which are operable in the concept of this invention may be any of the asphalts obtained from petroleum crude oils by processes known to the art. For example, those petroleum crudes having high asphaltic contents such as those of South America, for example, Lagunillas; California, such asSan Joaquin; or Mid-Continent ,crudes, may be used as the source for the asphaltic material. The petroleum crude oils are treated for removal of the lighter fractions by well-known methods, for example, steam distillation, vacuum flashing, or by solvent separation, e. g.,' butane or propane deasphalting.

It may also be desirable to oxidize the asphaltic materials obtained from the reduction of the petroleum crude by blowing with air or by any other means known to the art. As has been described before, oxidation of these asphaltic materials improve their properties of ductility,

increase their softening point, and reduce their brittleness.

natural-occurringasphalts with petroleum asphalts may also be used. I The asphaltic material operable in the concept of this invention may be any of the above-described natural or petroleum asphalts having viscosities in the range of from 200 to 2,000 Saybolt Furol at 300 F. Preferred, however, and contemplated in the preferred embodiment of this invention are those petroleum asphaltic materials having viscosities from about 240 to about 1200 Saybolt Furol at 300' F.

r DILUENT OIL As was stated above, the gist of the'instant invention lies inthe discovery that a diluent oil of low viscosity 'index and high aromatic content has greater solvent power for the asphaltic component of the blend. The diluent oils chosen will have viscosities at 210 F. within the range of from about 60 to about 360 SUS and will have aniline points (descriptive of the aromatic content) within;

the rangeof from about 80 to about 120 F. The viscosity indices of these solvent extracts will be between about 40 and about 350.

'These highly aromatic solvent extracts are obtained from naphthenic base oils such as coastal distillates, by

solvent extraction procedures which are known to. the

art such as phenolextraction, silica gel extraction, and the A preferred method of preparing a suitable diluent 011 15 by phenol extraction of a coastal distillate.

be understood, of course, that mixtures of these diluent oils may be used.

ADDITIVE MATERIALS I v troleum asphalt and a highly aromatic diluent oil. It-

It will,

should be understood, however, that other additive materials may be blended with these components to improve the final characteristics of the blend. For example, tackiness of the lubricant may be improved by adding to the blend from 1 to 5 Wt. percent of high molecular weight polymers and copolymers such as polyisobutylene, copolymers of isobutylene and styrene, and the like.

For example, a blend of 45.0 wt. percent of asphalt A with 55.0 wt. percent of diluent oil C containing 2.16 wt. percent of a polyisobutylene of 21,000 mol. wt., Staudinger, gave a gear rig test life that was 2.5 hours longer than the same blend without the polyisobutylene. In another example, a blend of 46.0 wt. percent of asphalt B and 53.5 wt. percent of diluent oil C containing 0.5 wt. percent of a polymer of isobutylene and styrene having a styrene content of 50% had a gear rig life of more than 36 hours.

It is also contemplated that volatile solvents may be added to the: gear lubricants of this invention to reduce their viscosity temporarily for purposes of application. These volatile solvents such as 300 -500 F. boiling range petroleum distillates and chlorinated hydrocarbons, e. g., trichloroethylene, etc., evaporate after application, leaving a film of higher viscosity material deposited upon the metal surfaces to be lubricated.

PROPORTIONS The proportions used to prepare the open gear lubricants of this invention will depend upon the viscosity of the starting materials and the viscosity desired in the final blend. Ordinarily, however, it is desired that the final lubricant have a viscosity between about 1,000 and 6,000 SUS at 210 F. for best lubricating results. Thus, from about 20 .to about 90' wt. percent of the asphalt may be blended with about 80 to about 10 wt. percent of the diluent oil. A preferred range, and one operable with most asphaltic materials and diluent oils will be between about 40 to wt. percent of the asphalt with about 60 to 30 wt. percent of the diluent oil.

The amount of additive materials blended with the gear lubricants will also depend upon the characteristics of the desired final product. Ordinarily, from about 0.2 .to about 5.0 wt. percent. of such additives as polymers of isobutylene and copolymers of isobutylene with other p'olymerizable monomers may be used. A preferred range is about 0.6 to about 3.0 wt. percent.

The volatile solvent may be used in amounts varying between about 5.0 and 20.0 wt. percent, preferably about 10.0 to about 15.0 wt. percent. a

To summarize briefly, this invention relates to im proved open gear lubricants which comprise an asphaltic material such as a reduced or reduced and oxidized asphalt blended with a diluent oil which is highly aromatic in nature and which has a viscosity index between about 40 and 350 and an aniline point of about to about"120 F. The diluent oil is preferably phenol' extract from a coastal distillate, having a viscosity index of about 40 toabout 330, a viscosity of 210 F. of about 60 to 360 SUS, and an aniline point of between about and about F.

' The improved open gear lubricants of this invention may contain minor amounts of additive materials known -to the art without departing from the spirit thereof.

Volatile solvents such as trichloroethylene, petroleum solvents, and similar materials may also be contained in the finalformulation. Whatis claimed is:

1. An improved open gear lubricant having a viscosity of 1,000 to 6,000 SUS at 210 F. consisting essentially of a blend of from about 40 to 60 wt. percent of an asphaltic material selected from the group consisting of reduced and reduced and oxidized asphalts with about 60 to 30 wt. percent of a highly aromatic solvent extract oil, said extract oil having a viscosity of 210 F. of about 60-360 'SUS, a viscosity index offrom about 40 to -330 and an aniline point between about 90 and 120 F., percentages being by weight based on the weight of the total composition.

2. An improved gear lubricant according to claim 1 which contains combined therein about 0.6 to 3.0 Wt. percent of a polymer of styrene and isobutylene having a styrene content of about 50% 3. An improved open gear lubricant having a viscosity of about 5,500 SUS at 210 F. consisting essentially of a blend of from about 68 Wt. percent of a reduced and oxidized asphalt with about 32 wt. percent of a highly aromatic phenol extract of a naphthenic distillate having a viscosity of 143 SUS at 210 F., a viscosity index of about 235 and an aniline point of about 111 F.

References Cited in the tile of this patent UNITED STATES PATENTS OTHER REFERENCES Motors Oils, by Georgi, Reinhold Pub. Co., 1950, 

1. AN IMPROVED OPEN GEAR LUBRICANT HAVING A VISCOSITY OF 1,000 TO 6,000 SUS AT 210*F. CONSISTING ESSENTIALLY OF A BLEND OF FROM ABOUT 40 TO 60 WT. PERCENT OF AN ASPHALTIC MATERIAL SELECTED FROM THE GROUP CONSISTING OF REDUCED AND REDUCED AND OXIDIZED ASPHALTS WITH ABOT 60 TO 30 WT. PERCENT OF A HIGHLY AROMATIC SOLVENT EXTRACT OIL, SAID EXTRACT OIL HAVING A VISCOSITY OF 210*F. OF ABOUT 60-360 SUS, A VISCOSITY INDEX OF FROM ABOUT-40 TO-330 AND AN ANILINE POINT BETWEEN ABOUT 90* AND 120*F., PERCENTAGES BEING BY WEIGHT BASED ON THE WEIGHT OF THE TOTAL COMPOSITION. 